Circuit breaker



May 2, 1939.

J. G. JACKSON 5 AL CIRCUIT BREAKER Filed Oct. 31,- 1935 3 Sheets-Sheet 1III INVENTOR5.

BYWWV ATTORNEY.

May 2, 1939.

CIRCUIT BREAKER 3 Sheets-Sheet 2 Filed Oct. 51, 1935 1 OM \IA m a i A A9Z m w 615 O Z 7 5, L 3 V (w l 5 v H mmmwm 5 w m; A MT y 1939- J. 3.JACKSON ET AL 2,156,761

C IRCUIT BREAKER Filed on. 51, 1955 3 Sheets-Sheet 3 l 4/ 5/ d 4a l v 0O 26 "Z E4 I 35 9 I 9 l v 6 rig INVENTORS.

ATTORNEY Patented May 2,1939 2 15 7 1;

UNITED STATES PATENT OFFICE CIRCUIT BREAKER John G.-Jackson and Wallace'1'. Allen, Detroit,

Mich.,-assignors to Square- D Company, Detroit, Mlch., a corporation ofMichigan Application October 31, 1935, Serial No. 47,525

19 Claims. (Cl. 200-116) This invention relates to automatic electric Inthe embodiment specifically illustrated and decircuit breakerapparatus-and automatic circuit scribed there is showna unit comprisedof two breaker mechanisms. groups of four electrically common mechanismsOne object of this invention is to provide an on a common base. Itis,'of course, readily unimproved grouping of automatic electric circuitderstood that any number of individual mecha- 5 breakers having commonelectrical and mechannisms may be included in any group and that anyical features. number of separate groups may be mounted in a Anotherobject of this invention is to provide a single enclosing box orcabinet. As the separate group of automatic electric circuit breakerssealgroups in the unit are entirely distinct electrically l0 ablysupported over a common bus. and also mechanically except for the common10 Another object of this invention is to provide a mounting on the basein the box, only one of group of electric circuit breakers sealableagainst. these groups will be hereinafter described. outside tamperingbut provided with communi- The group comprises an insulating base 8secating passageways allowing common venting of cured to the back of thebox by the studs 4.

iii are gases. The front face of this base is provided with a f Anotherobject of this invention is to provide plurality of aligned supports 5upon which is an improved. and economical formof circuit rigidly secureda bus bar 8 by means of studs I. breaker mechanism. These studs mayextend from the back of the base Another object of this invention is toprovide and be waxed in place to mount the bus bars on circuit breakerapparatus including an outer box the base in a relatively permanentfashion. A 20 enclosing a scalable group of circuit breakershavconnection stud 'I' is provided on the exposed ing improved featuresof simplicity and economy end of the bar. Over the bus 6 are disposed aand common mounting features. plurality of individual cup-shapedinsulating Another object of this inventionris to provide members 8inwhich are supported the individual an improved form of automaticallyand manually circuit breaker mechanisms. The opposite walls 25 openablecircuit breaker mechanism, the autoof these members are cut out to fltover the bus matic circuit opening being trip-free of the opso thattheir outer walls extend into close fittin crating handle. engagementwith the base 3. The members 8 are Other objects and features of thisinvention will secured in position by studs 9 which are threaded '30 bereadily apparent to those skilled in the art into the bus 6 and serve torigidly secure the from the following specification and theappendmembers in position. The head of this stud is ed drawingsillustrating certain preferred embodwaxed in place to form sealedenclosures for the iments of the invention in which: circuit breakermechanisms.

Figure 1 is a top plan view of the circuit breaker Within each of themembers 8 the bus bar is apparatus according to the present inventionwith provided with a stationary contact I I rigidly sup- 5 the outercover broken away. I ported thereby. A conductor i2 is supported onFigure vii is a fragmentarysectional view taken the member 8 by stud l8,which is waxed in place, on line 11-11 of Figure 1. and supports asecondary stationary contact ll Figure 3 is a sectional view taken onthe line thereon. A bridging conductor I5 is provided in III-III ofFigure 1. with contact surfaces adjacent its opp site ends Figure 4 is afragmentary sectional view taken for cooperation with the contacts IIand M on on the line IV-IV of Figure 3. the bus 6 and the conductor l2.The conductor Figure 5 is a fragmentary sectional'view of the I5 issupported on the end of a rod l6 which is breaker shown at the right inFigure 3 but showslideably received within a generally cup-shaped ingthe parts in manual foif position. member H. A compression spring I8 isdisposed Figure 8 is a view similar to Figure 5 with the between thehead of the rod I 8 and the member I! parts in the resetting position.normally tending to move the headed end of the The circuit breakerapparatus illustrated in the rod away from the member. The member I1 isdrawings comprises an outer sheet metal enprovided with aslot 19 at thebottom and at closing box I having an openable cover 2 hingedone .sidethereof within which slot is pivotally ly or otherwise mounted thereonin a convenmounteda latch 2| having. a latching surface 22 tionalmanner. This box may be equipped with adapted to engage in a latchin'gnotch 28 on the the usual knockouts, cover latch or similar fearod IS.The rod I8 is also provided with a longiands conventional in the art.Within this tudinal slot 28 on its periphe providing clearouter box ismounted a group of circuit breakers. ance for the latch 2| in themovement of the rod l8. The latch 2| is normally maintained in latchingposition by a member 24 pivoted on the cup-shaped supporting member 8 asat 25.

A bimetallic strip 26 is rigidly mounted at one end upon the conductorl2 and extends upwardly therefrom with its free end provided with alatching element 21 for the latch retaining member 24. A flexible lead28 connects the free end of the bimetallic strip 26 with the outsidecircuit connector 29.

An operating push button 8| in the form of an inverted cup-shaped memberis mounted over 'themember l1 and is movable with relation thereto bothlongitudinally and rotatably. This movement may be secured by theenlarged peripheral groove 32 in the member i1 within which are disposedthe pins 88 on the push button 8|.

The push button is inserted in position by theures and 6 in which isshown the latching surface .81 which engages with the latching element21' on the free end of the bimetallic element 26. The under part of onearm of the member 24 is provided with a notch 38 adapted to receive apin 38 mounted on the member l1 for a purpose to be hereinafterdescribed.

The push button 3| is provided with exterior locking lugs 4| slideablewithin the grooves 42 in the top of the cup-shaped member 8 androtatable beneath the top of said member to hold the push button in theon position.

. The operation of the individual mechanism-will now be described.

The mechanism as shown in Figure 2 and at the right in Figure 3 is inthe normal on position. The push button 3| has been pressed in androtated whereupon the lugs 4| having passed through the grooves 42 arenow disposed beneath the top of member 8 and secure the push button 3|in an interior position. The compression spring has been stressed by thepressing of the push button and stresses the member toward the base. Themember l1 and rod l6 are securely latched together by the latch 2| andthe bridging conductor i5 is held in its circuit closing position withthe contact pressure maintained by the spring 85.

To manually separate the contacts the push button 3| is rotated back inposition where lugs 4| are beneath the grooves 42 whereupon the pushbutton is pulled outwardly moving the parts to their normal "o'fi"position with the bridging conductor i5 raised to its upper positionremote from the contacts II and H as shown in Figure 5. The operation toclosed circuit position is then as previously described.

Upon the occurrence of an overload the bimetallic strip 26 becomesheated and warps away from the member 24 which then rotates about itspivot 25 to release the latch 2|. This movement of the latch 2| and themember 24 occurs under the bias of the spring l8. As the latch isreleased the rod I8 is free to move upwardly to the. Dosition shown atthe left in Figure 3 carrying with it the bridging conductor l5 andbreaking the circuit through the breaker.

To reset the parts after an automatic separation of the contacts thepush button is rotated to the position where the lugs 4| are beneath thegrooves 42 and the push button is pulled upwardly as in the manualseparation of the contacts. Inthis operation the pin 39 engages in ;thenotch 88 in the member 24 and pulls it into the position where thelatching surface 31 engages the latching element 2'|-on the free end ofthe bimetallic strip 2| which in the meantime has moved back to itsnormal position. This upward movement of member 24 rotatesthe latch 2|back into its normal latching position. It is seen that this finalrotation will take place only in the extreme position of the push buttonat which time the member will have been moved upwardly to place thelatch in its proper relation to the rod l8 and thus stress the springI8. After the latching of the member 24, the parts will then be in theirnormal manual off" position and the circuit may be closed by pressingthe push button and rotating the lugs 4| into engagement with the undersurface of the top of the cup-shaped member 8.

The adjacent walls between the circuit breakers in the group are cutaway so as to provide communication'between their interiors to permitthe gases generated by the opening of the circuit through any circuitbreaker mechanism to be expelled throughout the interiors of all thecircuit breakers in the group, thus rendering less necessary any vent tothe outer air.

The connector I at the end of bus 8 may be utilized as a bus tap or as amain terminal for the breakers. When used as a main terminal theindividual circuit breaker mechanisms will each lead to a separatecircuit; when used as a bus tap one of the circuit breakers willfunction as a main breaker leading to the bus 6 which in turn will feedthrough other individual mechanisms to the individual circuits. In thisarrangement the circuits fed through the load breakers will thus beprovided with main and branch protection having at all times two circuitbreakers in series with any short which may occur. However, when theextension 8 is used as a bus tap, feeding therefrom will be only throughthe main breaker. In some instances it I may be desirable to cut oil thebus 8 within the last circuit breaker interior of each group and toclose the opening in the end wall of the group whereupon the feeding tothe branch circuit will always be through two circuit breaker mechanismswhereof one provides main protection to all the branch circuits and theother individual mechanisms provide branch protection for theirindividual circuits.

In the appended claims the terms "box and cover are to be construed toinclude cabinet and door respectively.

While certain preferred embodiments of the invention have beenspecifically disclosed, it is understood that the invention is notlimited thereto as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims:

What is claimed is:

1. Electric circuit breaker apparatus comprising an insulating base, a,conductor mounted on said base, a plurality of cup-shaped insulatingmembers mounted over said conductor and cooperating with said base toform sealable enclosures, a circuit breaker mechanism within eachenclosure and an operating member for each mechanism projecting throughthe enclosures.

2. Electric circuit breaker apparatus comprising an insulating base, aconductor mounted on said base, a plurality of cup-shaped insulatingmembers mounted over said conductor and cocoperating with said base toform scalable enclosures, a circuit breaker mechanism within eachenclosure and an operating member for each mechanism projecting throughthe enclosures, a stationary contact, for each circuit breaker beingdirectly supported by the conductor within the enclosures.

3. Electric circuit breaker apparatus comprising an insulating base, aconductor mounted on said base in spaced relation thereto, a plurality.of cup-shaped insulating members mounted over said conductor, the endwalls of said members being cut away to receive said conductor, thewalls of said members cooperating with each other and said base to formscalable enclosures, a circuit breaker mechanism within eachenclosureand an operating member for each mechanism projecting through theenclosures.

4. Electric circuit breaker apparatus compris ing an insulating base, aplurality of individual enclosures mounted over said base in scalablerelation, individual circuit breaker mechanisms within the enclosures,the interiors'of said'enclosures being in direct communication wherebythe gases formed by an are drawn upon the operation of any one mechanismmay be vented to the other enclosure interiors.

5. Electric circuit breaker apparatus comprising an enclosing box, aplurality of scalable circuit breaker enclosures within said box, saidenclosures having direct communication without opening to the box andsealed from exterior access whereby the gases formed by an are withinany enclosure may be vented throughout the enclosure interiors.

6. Electric circuit breaker apparatus comprising an insulating base, abus bar mounted on said base, a plurality of individual circuit breakermechanisms mounted in individual enclosures attached to said bus bar andcooperating with said base to sealably enclose said mechanisms and bus'bar, one contact of each of said mechanisms being supportedby said busbar.

7. Electric circuit breaker apparatus compris ing a plurality ofcup-shaped insulating bases, individual circuit breaker mechanismsmounted in said bases, an insulating plate, a bus bar sup- ,ported bysaid plate, one contact for each mechanism being supported by said busbar, and means for sealably mounting said bases on said plate to enclosesaid mechanisms and bus. bar with said one contact in position tocooperate with their respective mechanisms.

8. Electric circuit breaker apparatus comprising a plurality ofcup-shaped insulating bases,

individual circuit breaker mechanisms mounted 9. An electric circuitbreaker including spacedstationary contacts, a reciprocable conductorhaving contact faces adjacent to its end and adapted to bridge saidcontacts, an element connected to said conductor, a second elementmovadapted to bridge said contacts, an element connected to saidconductor, a second element movable relative to said first mentionedelement, a latch connecting said elements for common movement, a latchretaining member pivotally mounted on a stationary part, a currentresponsive latch for said member, a spring biasing said elements forrelative movement, a push button movably connected to said secondelement, a.

spring biasing said push button relative to said second element, astationary latching surface for said push button, said push buttonengaging said surface by manual rotation, the last mentioned springmaintaining pressure between said contact faces and contacts.

11. In an automatic electric circuit breaker, stationary and movablecontacts, a reciprocable element connectedto said movable contact, a

second reciprocable element slidably receiving said first element, aspring biasing said elements for relative movement, a latch pivoted onsaid second element and engaging a surface on said first element,release of said latch permitting said first element to move said movablecontact to open position under the actionof said spring, a latchretaining member pivoted on a stationary part and normallysiidablyengaging said latch and a current responsive holding means for saidmember.

12. In an' automatic electric circuit breaker, stationary and movablecontacts, a reciprocable element connected to said movable contact, asecond reciprocable element slidably receiving said first element, aspring biasing said elements for relative movement, a latch pivoted onsaid second element and engaging a surface on said first element,release of said latch permitting said first element to move said movablecontact to open position under the action of said spring, a latchretaining member pivoted on a stationary part and normally slideablyengaging said latch,

a current responsive holding means for said member, a push buttonslideably receiving said second element, a spring forming the operativeconnection between said push button and second element in one directionand means for latching said push button with said spring compressed toexert pressure between the cooperating contacts.

13. In an automatic'electric circuit breaker, stationary and movablecontacts, a reciprocable element connected to said movable contact, a

second reciprocable element slideably receiving said first element, aspring biasing said elements for relative movement, a latch pivoted onsaid second element and engaging a surface onsaid first element, releaseof said latch permitting said first element to move said movable contactto open position under the action of said spring, a latch retainingmember pivoted on a stationstationary and movable contacts, areciprocable element connected to said movable contact, a secondreciprocable element slideably receiving said first element, a springbiasing said elements for relative movement, a latch pivoted on saidsecond element and engaging a surface on said first element, release ofsaid latch permitting said first element to move said movable contact toopen position under the action of said spring, a latch retaining memberpivoted on a stationary part and normally slideably engaging said latch,I

a current responsive holding means for said member, a push button'slideably receiving said second element, a spring forming the operativeconnection between said push button and second element in one direction,means for latching said push button with said spring .compressed toexert pressure between the cooperating contacts, and a pin on saidsecond element adapted to cooperate with said member to reset said partsupon outward movement of said push button after an automatic operation.

15. Electric circuit breaker apparatus comprising a commonconductorcarrying a plurality of contact faces thereon, a plurality of insulatingbases mounted over said conductor, said bases having compartmentstherein receiving individual automatic electric circuit breakermechanisms having movable contact surfaces adapted to cooperate with thecontact faces on the conductor to perform the switching operation, saidmechanisms being sealed within their compartments from exterior accessand at least certain of said compartments being in communication toprovide a common venting chamber for the mechanisms in said certaincompartments for the gases generated by an are formed between saidcontact faces and surfaces.

16. Electric circuit breaker apparatus comprising a common conductorcarrying a plurality of contact faces thereon, a plurality of insulatingbases mounted over said conductor, said bases having compartmentstherein receiving individual automatic electric circuit breakermechanisms having movable contact surfaces adapted to cooperate with thecontact faces on the conductor to perform the switching operation, saidmechanisms being sealed within their compartments from exterior accessand at least certain of said compartments being in communication toprovide a common venting chamber for the mechanisms in said certaincompartments for the gases generated by an are formed between saidcontact faces and surfaces, and insulating formationsin back of saidcommon conductor and connected to said bases'to substantially enclosethe main body of said conductor.

17. Electric circuit breaker apparatus comprising a common conductorcarrying a plurality of contact faces thereon, a plurality of insulatingbases mounted over said conductor, said bases having compartmentstherein receiving individual automatic electric circuit breakermechanisms having movable contact surfaces adapted to cooperate with thecontact faces on the conductor to perform the switching operation, saidmechanisms being sealed within their compartments from exterior accessand at least certain of said compartments being in communication toprovide a common venting chamber for the mechanisms in said certaincompartments for the gases generated by an arc formed between saidcontact faces and surfaces, insulating formations in back of said commonconductor and connected to said bases to substantially enclose the mainbody of said conductor, and a portion on said conductor extending beyondsaid bases and serving as a terminal for the attachment of circuit wiresleading current to said individual mechanisms.

18. Electric circuit breaker apparatus comprising a common conductorcarrying aplurality of contact faces thereon, a plurality of insulatinghaving compartments. therein receiving individual automatic electriccircuit breaker mechanism having movable contact surfaces adapted tocooperate with the contact faces on the conductor to perform theswitching operation, said mechanisms being sealed within theircompartments from exterior access, and insulating formations in back ofsaid common conductor and connected to said bases to substantiallyenclose the main body of said conductor.

19. Electric circuit breaker apparatus comprising a common conductorcarrying a plurality of contact faces thereon, a plurality of insulatingbases mounted over said conductor, said bases having compartmentstherein receiving individual automatic electric circuit breakermechanisms having movable contact surfaces adapted to cooperate with thecontact faces on the conductor to perform the switching operation, saidmechanisms being sealed within their. compartments from exterior access,and mating openings in certain adjacent walls of said bases cooperatingto provide communication between certain of said compartments and acommon space for the dissipation of gases generated by arcs formedbetween the contact faces and surfaces of the mechanisms in said certaincom partments. t

- JOHN G. JACKSON.

WALLACE T-. ALLEN.

,bases mounted over said conductor, said bases column, line 3, claim 15,strike outvthe words hissing said elements" and insert instead member,

element; and that the said Letters Patent should be read with thiscorrec-' tion therein that the same may conform to the record of thecase in the Pat- CERTIFICATE OF CORRECTION. Patent No. 2,156,761. May 2,1959.

' JOHN G. JACKSON, ET AL. It is hereby certifiedthat error appears inthe printed specification of the above numbered. patent requiringcorrection as follows: Page first "first element, a spring ent Office vSigned and sealed this 20th day of June, A. D. 1939.

Henry Van Arsdale Acting Commissioner of, Patents.

and a pinon said second. Y

column; line 3, claim 15, strike outthe words hiesing said elements" andinsert instead member, element; and that the said Letters Patent shouldbe read with this cor'rec-' tion therein that the same may conform tothe record or the case in the Pat- CERTIFIGA'I'E OF CORRECTION. PatentNo. 2,156,761. May 2, 19 9. c i

JOHN G. .mcxson, ET AL. It is hereby certifiedthat error appears in theprinted specification of the above numbered. patent requiring correctionas follows: Page first "first element, e spring ent' Office 4 signed andsealed this 26th day of June, A. D. 19 9.

Henry Van Arsdale Acting Commieeioner of! Patents.

and a pin on said eecond

